Date v Math as Instance v Static

[Robert Mark Bram]

Howdy All!

I am trying to write a very brief comparison of the Date and Math objects in
terms of instance v static objects. What I have below is my best so far. Any
criticisms or suggestions are most welcome!

Date is an instance object.
You use Date by creating instances of it
- you call methods on those instances.
- you change data to do with each instance.
Instance objects store state
- meaning they hold data that may change over time.

Math is a static object.
You never create instances of it
- you call methods on Math directly.
- it never stores data for you: each method performs some mathematical
computation and returns a result. It is up to you to store required data.
Static objects can store state - but Math does not.

Rob
:)

[Douglas Crockford]

Re: Date v Math as Instance v Static

> I am trying to write a very brief comparison of the Date and Math objects in[color=blue]
> terms of instance v static objects. What I have below is my best so far. Any
> criticisms or suggestions are most welcome!
>
> Date is an instance object.
> You use Date by creating instances of it
> - you call methods on those instances.
> - you change data to do with each instance.
> Instance objects store state
> - meaning they hold data that may change over time.
>
> Math is a static object.
> You never create instances of it
> - you call methods on Math directly.
> - it never stores data for you: each method performs some mathematical
> computation and returns a result. It is up to you to store required data.
> Static objects can store state - but Math does not.[/color]

Date is a constructor function. Functions are objects, so it can act as a
container of [static] functions.

Math is not a function, it is just an object. It acts as a container for a
collection of functions.

http://www.crockford.com/#javascript